The present invention relates to an image generating apparatus which generates monitor image data from camera image data through a viewpoint transformation using a virtual camera and a virtual projection plane, and to an image generating method.
As driving assistance devices, one disclosed in Japanese Patent Application Laid-Open Publication No. 2005-236493 has been heretofore known. The disclosed driving assistance device aims to provide a driver with an easy-to-understand image while changing a screen configuration and a viewpoint position in response to a move of a vehicle. To this end, the disclosed driving assistance device switches a single viewpoint image and a multi-viewpoint image in response to every move of the vehicle. The single viewpoint image is displayed as a downward view in which multiple camera images shot by multiple imaging devices are viewed from a single viewpoint, and the multi-viewpoint image is an image in which multiple camera images are respectively displayed on divided screens.
In addition, as conventional image generating apparatuses, one disclosed in Japanese Patent No. 3286306 has been known. This disclosed image generating apparatus synthesized multiple images shot by several cameras into a single image, and displays the single image instead of displaying the multiple images independently, so that a situation of the entire area shot by the several cameras can be intuitively grasped.
However, the driving assistance device described in Japanese Patent Application Laid-Open Publication No. 2005-236493 described above has a problem that a user is required to perform a selecting operation between the single viewpoint image and the multi-viewpoint image in order to grasp a situation around the vehicle. This operation is necessary because, the single viewpoint image shows only a close view by displaying a downward image, while the multi-viewpoint image shows only distant views by displaying camera images. In addition, since both of the single viewpoint image and the multi-viewpoint image are displayed by using multiple camera images, both types of images have problems that no continuity exists in a synthesis image and divided images, and that double shooting of the same image or image missing occurs.
The image generating apparatus described in Japanese Patent No. 3286306 is intended for displaying, as a single synthesis image, a situation of the entire area shot by the several cameras. Accordingly, in order to provide continuity to the synthesis image, the image generating apparatus needs to be provided with: a discriminative point extraction means for extracting discriminative points from multiple camera images, and a calibration means for calibrating a display image by using the multiple discriminative points. Consequently, the calculation processes for generating monitor image data become complicated. On the other hand, an absence of the discriminative point extraction means and the calibration means causes the problems of no continuity in a synthesis image, double shooting of the same image, and image missing.